Video processing and optical recording using a shared memory

ABSTRACT

A combined digital TV decoding and optical recording system includes a transport stream demultiplexer to demultiplex at least one compressed multimedia stream from an MPEG transport stream having multiplexed compressed multimedia streams. A video encoder compresses a video stream to generate a second compressed video stream. A common system controller controls operations of the transport stream demultiplexer and the video encoder, and allocates portions of a memory to the transport stream demultiplexer and the MPEG video encoder based on respective memory requirements.

BACKGROUND

This description relates to video processing and optical recording.

In one example, a digital television signal includes modulatedmultiplexed transport stream signals that are compressed according to,e.g., MPEG (Moving Picture Experts Group) standard, defined in ISO/IECMPEG specification, also referred to as ISO/IEC 13818, hereinincorporated by reference. The MPEG encoded signals are modulated using,e.g., vestigial side band (VSB) modulation or quadrature amplitudemodulation (QAM). The digital television signal may comply with, e.g.,ATSC (Advanced Television Systems Committee), DVB (Digital VideoBroadcasting), or ISDB (Integrated Services Digital Broadcasting)standard.

A viewer of a digital TV program uses a digital TV processing module,such as a set top box or an integrated receiver, to process the digitalTV signal and generate analog audio and video signals that can be outputto speakers and a display (e.g., a cathode ray tube or a flat paneldisplay). The digital TV processing module includes a system controllerto control processing of the digital TV signal, including demodulation,MPEG decoding, video post-processing, and TV encoding, such as PAL(phase-alternating line), NTSC (National Television Systems Committee),or SÉCAM (sequentiel couleur avec mémoire) encoding. A dynamic randomaccess memory (DRAM) is provided in the set top box to store data duringprocessing of the digital TV signal.

A DVD recording system can store multimedia data on a digital versatiledisc (DVD) that complies with standards established by DVD Forum. In oneexample, audio and video signals are compressed and multiplexedaccording to the MPEG standard, and channel encoded according to the DVDstandard. The DVD recording system includes a system controller tocontrol processing of the audio and video signals, including MPEGencoding and EFM+ (eight-to-sixteen) modulation. A DRAM buffer isprovided in the DVD recording system to store data during the processingof the audio and video signals.

The DVD recording system typically includes playback functionality, inwhich multimedia data retrieved from the DVD disc are processed togenerate analog audio and video signals that can be output to thespeakers and the display. The system controller in the DVD recordingsystem controls processing of the data retrieved from the DVD disc,including EFM+ demodulation and MPEG decoding. The DRAM buffer in theDVD recording system is used to store data during processing of the dataread from the DVD disc.

The system controller and DRAM of the digital TV signal processingmodule operate independently of the system controller and DRAM of theDVD recording system.

SUMMARY

In general, in one aspect, the invention features an apparatus thatincludes a transport stream demultiplexer to demultiplex at least onecompressed video stream from an encoded transport stream havingmultiplexed compressed video streams, a video encoder to compress avideo stream to generate a second compressed video stream, and acontroller to allocate portions of a shared memory to the transportstream demultiplexer and the video encoder based on respective memoryrequirements.

Implementations of the invention may include one or more of thefollowing features. The apparatus includes a common memory controllerfor controlling access to the memory by the transport streamdemultiplexer and the video encoder. The apparatus includes ademodulator to demodulate a signal from a digital television tuner togenerate the encoded transport stream. The apparatus includes arecording module to record at least one of the compressed video streamsdemultiplexed by the transport stream demultiplexer and the secondcompressed video stream to a recording medium. The apparatus includes atransport stream to program stream encoder to convert the demultiplexedcompressed video stream into an MPEG program stream. The apparatusincludes a program stream to transport stream encoder to convert thesecond compressed video stream into an MPEG transport stream. Theapparatus includes at least one of a video decoder, a videopost-processor, an audio encoder, and an audio decoder, in which thecontroller allocates portions of the shared memory to the at least oneof the video decoder, the video post-processor, the audio encoder, andthe audio decoder based on respective memory requirements.

In general, in another aspect, the invention features a system thatincludes a demodulator to demodulate a signal from a digital televisiontuner to generate an MPEG transport stream having multiplexed compressedvideo streams, a transport stream demultiplexer to demultiplex at leastone compressed video stream from the MPEG transport stream, an MPEGvideo decoder to decode the compressed video stream, an MPEG videoencoder to compress another video stream to generate a second compressedvideo stream, and a memory shared by the transport stream demultiplexer,the MPEG video decoder, and the MPEG video encoder. The system includesa controller to control the transport stream demultiplexer, the videodecoder, and the video encoder, and allocate portions of the sharedmemory to the transport stream demultiplexer, the video decoder, and thevideo encoder based on respective memory requirements. The systemincludes a recording module to record at least one of the compressedvideo streams demultiplexed by the transport stream demultiplexer andthe second compressed video stream to a recording medium.

In general, in another aspect, the invention features a system thatincludes a system controller to control operations of a first module fordecoding a digital TV signal and a second module for encoding a videosignal for recording to an optical recording medium, and a systemresource shared by the first and second modules, the system controllerallocating portions of the system resource to the first and secondmodules based on requirements of the modules.

Implementations of the invention may include one or more of thefollowing features. The system resource includes memory. The systemcontroller adjusts speeds of the first and second modules so that peakrequirements of the system resource from the first and second modulesoccur at controlled times. The first module includes an MPEG decoder todecode the MPEG encoded audio and video signals. The second moduleincludes an MPEG encoder for compressing the video signal according toMPEG encoding to generate a compressed video signal.

In general, in another aspect, the invention features a system thatincludes means for dynamically allocating portions of a shared memoryfor use in (a) demultiplexing a signal having multiplexed digitallyencoded video streams and (b) encoding another video stream, and meansfor simultaneously demultiplexing the signal and encoding the otherstream using the respective allocated portions of the memory.

In general, in another aspect, the invention features a system thatincludes a system controller to control operations of a first module fordecoding a digital radio signal and a second module for encoding anaudio signal for recording to an optical recording medium, and a memoryshared by the first and second modules, the system controller allocatingportions of the memory to the first and second modules based onrequirements of the modules.

In general, in another aspect, the invention features a method thatincludes dynamically allocating portions of a shared memory for use in(a) demultiplexing a signal having multiplexed digitally encoded videostreams and (b) encoding another video stream, and demultiplexing thesignal and encoding the other stream using the respective allocatedportions of the memory.

Implementations of the invention may include one or more of thefollowing features. The method includes controlling the demultiplexingand the encoding operations using a common controller. Demultiplexing asignal having multiplexed digitally encoded video streams includesdemultiplexing an MPEG transport stream having multiplexed MPEG encodedvideo streams to select one of the MPEG encoded video streams. Themethod includes converting a selected MPEG encoded video stream into anMPEG program stream, and storing data used during the conversion in theshared memory. The method includes encoding the MPEG program streamaccording to an optical storage standard to generate a signal suitablefor storage in an optical storage medium that supports direct recordingof an MPEG program stream, and storing data used during the encoding ofthe MPEG program stream in the memory. The method includes decoding theselected MPEG encoded video stream according to MPEG decoding, andstoring data used during the decoding in the shared memory. The othervideo stream is encoded to generate an MPEG program stream, and themethod also includes converting the MPEG program stream into an MPEGtransport stream, and storing data used during the decoding in thememory. The method includes encoding the MPEG transport stream accordingto an optical storage standard to generate a signal suitable for storagein an optical storage medium that supports direct recording of an MPEGtransport stream, and storing data used during the encoding of the MPEGtransport stream in the memory.

In general, in another aspect, the invention features a method thatincludes using a controller to control operations of a first module fordecoding a digital TV signal and a second module for encoding a videosignal for recording to an optical recording medium, and storing dataused during operations of the first and second modules in a sharedmemory, in which allocation of a first portion of the memory to storedata used by the first module is partially dependent on an operationcondition of the second module.

Implementations of the invention may include one or more of thefollowing features. The method includes dynamically allocating a firstportion of the memory to store data used during operations of the firstmodule, and dynamically allocating a second portion of the memory tostore data used during operation of the second module. The methodincludes adjusting speeds of the first and second modules so that peakrequirements of the memory from the first and second modules occur atcontrolled times. The method includes demodulating a digital TV signal.Operations of the first module include demultiplexing an MPEG transportstream derived from the demodulated digital TV signal to generate MPEGencoded audio and video signals. Operations of the first module includedecoding the MPEG encoded audio and video signals according to MPEGdecoding to generate decoded audio and video signals. Operations of thefirst module include video post-processing the decoded video signal toimprove image quality of the video signal. Operations of the firstmodule include encoding the post-processed signal to generate an encodedsignal that can be displayed on a television. Operations of the secondmodule include compressing the video signal according to MPEG encodingto generate a compressed video signal. Operations of the second moduleinclude encoding the compressed video signal according to an opticalstorage standard to generate a signal having a waveform suitable forstorage on an optical storage medium. Operations of the first moduleinclude converting an MPEG transport stream derived from the digital TVsignal into an MPEG program stream. Operations of the second moduleinclude converting an MPEG program stream derived from the video signalinto an MPEG transport stream.

In general, in another aspect, the invention features a computer programproduct that causes a controller to perform operations including settingregister values to control operations of a first module for decoding adigital TV signal and a second module for encoding a video signal forrecording to an optical recording medium, and dynamically allocating afirst portion of a memory to store data used during operations of thefirst module, and dynamically allocating a second portion of the memoryto store data used during operations of the second module.

In general, in another aspect, the invention features a method thatincludes using a common controller to control operations of a firstmodule for decoding a digital radio signal and a second module forencoding an audio signal for recording to an optical recording medium,and storing data used during operations of the first and second modulesin a shared memory, in which allocation of a first portion of memory tostore data used by the first module is partially dependent on anoperation condition of the second module.

All of the publications, patent applications, patents, and otherreferences mentioned are incorporated herein by reference. In case ofconflict with the references incorporated by reference, the presentspecification, including definitions, will control.

DESCRIPTION OF DRAWINGS

FIGS. 1-3 show diagrams of a combined digital TV decoding and opticalrecording system.

FIGS. 4-5 show signal flow diagrams representing the flow of signals inthe combined digital TV decoding and optical recording system.

DESCRIPTION

FIG. 1 shows a schematic diagram of a combined digital TV decoding andoptical recording system 100 that has a common system controller 102 anda common DRAM 104. The system controller 102 controls both a digital TVand an optical storage processing module 106, which executes a process108 for processing a digital TV signal, a process 110 for processingmultimedia signals to be recorded to an optical storage medium 114, anda process 112 for processing encoded multimedia signals retrieved fromthe optical storage medium 114. The DRAM 104 stores data generated bythe module 106 while executing the processes 108, 110, and 112. By usinga common system controller 102 and a common DRAM 104, system resourcescan be used more efficiently and the amount of memory can be reduced.

In one example, the system controller 102 is an embedded controller thatis embedded in an integrated circuit that includes an MPEG encoder anddecoder. The DRAM 104 can be, e.g., double data rate (DDR) DRAM.

A digital TV signal can be processed at the same time that multimediasignals are recorded to the optical storage medium 114. For example, auser may view a first digital TV program at the same time that a seconddigital TV program is being recorded onto the optical storage medium114. The system controller 102 allocates a first portion of the DRAM 104for decoding the digital TV signal, and allocates a second portion ofthe DRAM 104 for processing data recorded to or read from the opticalstorage medium 114. The system controller 102 determines the sizes ofthe first and second DRAM portions based on operation requirements, inwhich the sizes of the first and second DRAM portions may change overtime.

For example, the memory that is allocated for each process may depend onthe encoding or decoding standard that is being supported, the bandwidthof the input transport stream, and how many multiplexed streams arebeing processed.

In one example, a memory buffer of 512 mega bits (Mbits) is used toprocess two high definition TV signals having a total bandwidth of 1gigabytes per second. A memory buffer of 256 Mbits is used to process ananalog standard definition video signal and associated analog stereoaudio signals for storage in the optical storage medium 114. If separatesystem controllers were used to control the processing of the digital TVsignal and the processing of the multimedia signals for storage, onesystem controller would not know the system resource requirements of theprocesses controlled by the other system controller, so a memory of 768Mbits is used to accommodate the peak requirements of both processes.

In one example, by having the combined system controller 102 and acommon DRAM 104, only 512 Mbits of memory is used for processing thehigh definition TV signals and the analog multimedia signals. Whenexecuting the processes 108, 110, and 112, the amount of memory requiredto temporarily store data varies depending on the stage of theprocessing. The combined system controller 102 can determine when theprocesses 108, 110, and 112 will have peak memory requirements, andeither slow down or speed up one of the processes 108, 110, and 112 sothat the peak memory requirements from the three processes 108, 110, and112 do not occur at the same time, thereby allowing a smaller DRAM 104to be shared by the three processes 108, 110, and 112. The systemcontroller 102 can also adjust the quality of the encoding and decodingprocesses in response to the amount of memory resources available.

In another example, a combined system controller 102 and a common DRAM104 of 768 Mbits are used. While the memory size is the same as the casewhen separate controllers were used, sharing a common memory and acommon controller has the advantage that the controller has moreflexibility in allocating memory portions, and can improve the qualityof one process if the memory requirement of another process is reduced.In the example above, if instead of processing high definition TVsignals, standard definition TV signals were processed, more memory andbandwidth can be allocated for encoding the analog multimedia signals toimplement more complex encoding algorithms to achieve a highercompression ratio and/or a better audio/video quality.

Using a common system controller and a common DRAM 104 reduces componentcosts, circuit board size, and power consumption. For example, thetransport stream demultiplexer 115 and the video encoder 154 each uses aportion of memory as output buffer. When a shared memory is used, asingle output buffer in memory may be shared by both the demultiplexer115 and the video encoder 154. In addition, sharing of information amongthe three process 108, 110, and 112 would be more efficient by using acommon system controller. If two controllers were used, a morecomplicated hand-shaking protocol would be required for the twocontrollers to communicate with each other.

FIG. 2 shows a block diagram of an example of a combined digital TVdecoding and optical recording system 200, in which the optical storagemedium is a DVD disc 80. The DVD disc 80 can be a DVD−R, DVD+R, DVD−RW,DVD+RW, DVD-RAM, double layer DVD−R, double layer DVD+R disc, or otherrecordable or rewritable discs that support direct recording of MPEGprogram streams.

The system 200 includes components for processing a digital TV signaland components for processing signals to be written to and retrievedfrom the DVD disc 80. A command bus 82 is provided for transmittingcontrol information between the system controller 102 and othercomponents of the system 200. A memory bus is provided to allowcomponents of the system 200 to access the DRAM 104.

Processing of a Digital TV Signal

The following describes processing of a digital TV signal. A digitaltuner 90 receives a digital television signal 92 from, e.g., a cable oran antenna. The signal 92 includes audio and video signals that arecompressed using the MPEG standard and modulated using VSB or QAMmodulation. The tuner 90 filters the signal 92 to select a physicalchannel, and outputs a modulated transport stream 94.

The term “physical channel” refers to a channel having a specificbandwidth (e.g., 6 to 8 MHz) and occupies a particular frequency band.The physical channels have center frequencies that are spaced 6 to 8 MHzapart. Each physical channel may include an MPEG transport stream havingone or more programming channels, depending on the bit rate of theprogramming channels.

The term “programming channel” refers to a channel that includes audio,video, and auxiliary signals associated with a program, such as a movieprogram or a news program. Auxiliary signals may include, e.g.,captioning information. Each programming channel may have a bit rate of3 mega bits per second (Mbps) to 18 Mbps, depending on the programcontent and on whether the program is standard definition (having704×480 resolution for NTSC, 768×576 or 1024×576 for PAL) or highdefinition (having 1280×720 or 1920×1080 resolution).

The MPEG standard specifies two stream formats: a “program stream”format that is more suitable for error-free environments, and a“transport stream” format that is more suitable for error-proneenvironments, such as satellite and cable networks. A program streamincludes streams (e.g., a video stream, one or more audio streams, and aprivate data stream) that is associated with a single program. A programstream includes packets that have variable lengths, in which packetsfrom different streams associated with the same program aretime-multiplexed in the program stream. A transport stream can includestreams from one or multiple programs. A transport stream includespackets that have fixed-lengths—188 bytes, in which packets fromdifferent streams of different programs are time-multiplexed in thetransport stream.

A demodulator 96 demodulates the transport stream 94 according to VSB orQAM demodulation to generate an MPEG transport stream 98. A transportstream demultiplexer 115 demultiplexes the transport stream 98 toseparate the multiplexed programming channels into individualprogramming channels, and to separate video, audio, and auxiliarysignals in each programming channel into separate streams to be storedin the DRAM 104.

Some digital TV tuners 90 have built-in demodulators. In that case, theoutput of the digital TV tuner 90 is sent directly to the transportstream demultiplexer 115.

The video and audio signals output by the transport stream demultiplexer115 have been compressed according to the MPEG algorithm. A standarddefinition or high definition MPEG audio/video decoder 116 retrieves thevideo, audio, and auxiliary signals stored in the DRAM 104, and decodesthe signals to generate decompressed video 118, audio 120, and auxiliarysignals. The video decoding process includes inverse zigzag ordering,inverse quantization, inverse discrete cosine transformation, and motioncompensation. During motion compensation, reference frames such as intra(I) or predicted (P) frames are stored in the DRAM 104 and are used toreconstruct compressed frames such as P or bi-directional predicted (B)frames based on motion compensation vectors. The reconstructed P or Bframes may also be stored in the DRAM 104

The decompressed audio signals 120 are in digital format, which isconverted into analog signals 124 by an audio digital-to-analogconverter 122. The analog signals 124 can be output to audio speakers.

The decompressed video signal 118 is processed by a video post-processor126 that performs video post-processing, which may include, e.g., ade-blocking process to smooth the transitions between adjacentmacroblocks of an image, a de-ringing process to remove suddentransitions from one image to a subsequent image, a scaling process toscale the image to fit the resolution of the display or to meet aspecific requirement of the viewer, and a color space transformation toadjust the color profile of the image according to the color gamut ofthe display. During video post-processing, the post-processed video datais stored in the DRAM 104.

A TV encoder 130 encodes the post-processed video signal 128 into ananalog video signal 131 according to, e.g., PAL, NTSC, or SECAM standardso that the analog video signal 131 can be shown on a television. Somedigital televisions can accept the post-processed video signal 128directly, in which the TV encoder 130 is not required.

The system controller 102 uses the decompressed auxiliary signals forfunctions such as captioning, surround mode selection, menu screengeneration, and electronic program guide (EPG).

Playback From Optical Storage

When playing multimedia programs stored on the DVD disc 80, an opticalpickup head (not shown) reads data from the disc 80 and outputs amultimedia signal 132 that is channel encoded and EFM+ modulatedaccording to the DVD standard. A first signal processor 134 demodulatesand decodes the signal 132 according to the DVD standard, and stores themultimedia signal in the DRAM 104. The multimedia signal output from thefirst signal processor 134 includes audio and video signals that arecompressed according to the MPEG algorithm, and are processed by theMPEG audio and video decoder 116, the audio DAC 122, the videopost-processor 126, and the TV encoder 130 similar to the processesdescribed above for processing of the digital TV signal 92.

Processing of Multimedia Signals for Optical Storage

Analog multimedia signals can be processed for storage to the DVD disc80. An analog audio signal 140 can be received from, e.g., an analogtelevision tuner (not shown), audio line-in jacks that receive separateleft and right audio channels (and additional surround sound channels),or from a composite input. An analog video signal 142 can be receivedfrom, e.g., an analog television tuner (not shown), video line-in jacksthat receive separate red, green, and blue color signals, or from acomposite input. The analog audio and video signals 140 and 142 areconverted to digital format by an audio analog-to-digital converter(ADC) 144 and a video ADC 146, respectively. Digital audio and videosignals 156 and 158 can also be provided from a digital co-axial cableor a fiber optic cable.

The digital audio and video signals 148 and 150 are encoded by an MPEGaudio encoder 152 and an MPEG video encoder 154, respectively, accordingto the MPEG standard. The encoding process includes, e.g., defining Iframes, compressing the I frames using intraframe compression, andcompressing P and B frames using motion compensation to generate motionvectors that represent movements and differences between macroblocks inthe P or B frames and macroblocks in the I-frame. After motioncompensation is performed, discrete cosine transformation, quantization,run length coding, and zigzag ordering of data are used to furthercompress the multimedia signals. During the encoding process, the I andP frames are stored in the DRAM 104 for use in determining motionvectors for P and B frames.

The MPEG audio encoder 152 and video encoder 154 compresses the audioand video signals, respectively, so that a standard definitionmultimedia program having a bit rate of about 50 Mbps can be compressedto about 3 Mbps, and a high definition multimedia program having a bitrate of about 270 Mbps can be compressed to about 18 Mbps.

A program stream multiplexer 160 retrieves the compressed audio andvideo signals from the DRAM 104, and multiplexes the audio and videosignals to generate a program stream. The program stream includes packetheaders, each followed by a number of packetized elementary stream (PES)packets. The packet header includes control information, such as apresentation time stamp that indicates when the multimedia content inthe PES packet is to be output (e.g., to a display and speakers). Theprogram stream multiplexer 160 stores the program stream havingmultiplexed audio and video signals in the DRAM 104.

A second signal processor 162 retrieves the program stream from the DRAM104, and encodes the program stream into a format suitable for storagein a DVD disc, including adding identification codes, scrambling, errorcorrection encoding, and applying EFM+ modulation according to the DVDstandard. The second signal processor 162 generates a modulated programstream 164 to drive a laser pickup head (not shown) to write themodulated program stream 164 in the DVD disc 80.

A transport stream to program stream encoder (abbreviated as TS-to-PSencoder) 166 is provided to convert the transport stream signalgenerated by the transport stream demultiplexer 115 into a programstream format. The program stream can then be processed by the secondsignal processor 162 for storage in the DVD disc 80. This allows a userto store digital TV programs in the DVD disc 80. An example of theTS-to-PS encoder 166 can be found in U.S. patent application Ser. No.11/086,543, filed Mar. 22, 2005, titled “Systems and Method for StreamFormat Conversion,” herein incorporated by reference.

System Controller

The system controller 102 controls operations of the modules in thesystem 200 by setting values of registers in the system 200 at variousstages of the processes. For example, the viewer may watch a digital TVprogram while storing the program in the DVD disc 80. The systemcontroller 102 controls the demodulator 96, the transport streamdemultiplexer 115, the MPEG decoder 116, the audio DAC 122, the videopost processor 126, and the TV encoder 130 according to interrupts orstatus information sent from those units to allow a digital TV programto be shown on a television. At the same time, the system controller 102controls the transport stream demultiplexer 115, the TS-to-PS encoder166, and the second signal processor 162 according to the interrupts orstatus information sent from those units, so that the digital TV programcan be stored in the DVD disc 80.

In another example, the viewer watches a digital TV program whilestoring a video from an analog camcorder (not shown) to the DVD disc 80.The operation of the system controller 102 in controlling processing ofthe digital TV signal is similar to that described above. At the sametime, the system controller 102 controls the audio and video ADCs 144and 146, the MPEG audio and video encoders 152 and 154, the programstream multiplexer 160, and second signal processor 162, so that theanalog video can be stored in the DVD disc 80.

In another example, the viewer watches an analog TV program whilestoring the analog TV program to the DVD disc 80. The analog audiosignal 140 and the analog video signal 142 can be sent to the speakersand the television to allow the user to view the analog TV program. Thesystem controller 102 controls the audio and video ADCs 144 and 146, theMPEG audio and video encoders 152 and 154, the program streammultiplexer 160, and the second signal processor 162 so that the analogvideo signal can be stored in the DVD disc 80, as described above.

In another example, the viewer watches a movie program stored in the DVDdisc 80 while at the same time watches a digital TV news program using apicture-in-picture function. The operation of the system controller 102in controlling processing of the digital TV signal is similar to thatdescribed above, except that the output of the digital TV program isoutput to a small window of the display rather than the full display. Atthe same time, the system controller 102 controls the first signalprocessor 134, the MPEG A/V decoder 116, the video post processor 126,the TV encoder 130, and the audio DAC 122 properly, so that themultimedia program in the DVD disc can be viewed on the display.

Alternative Example of the Combined Digital TV Decoding and OpticalRecording System

FIG. 3 shows a block diagram of an example of a combined digital TVdecoding and optical recording system 210, in which the optical storagemedium is a Blu-ray disc 212 that is compatible with the Blu-ray Discstandard established by the Blu-ray Disc Association. The Blu-ray disc212 can be, e.g., a recordable (BD Recordable), a rewritable (BDRecordable), or other optical discs that support direct recording ofMPEG transport streams. A Blu-ray Disc drive (not shown) is used toaccess the Blu-ray disc 212 and generate an output signal 133.

The system 210 includes a controller 102 for controlling various othermodules of the system 210, and a DRAM 104 to store data duringprocessing of the digital TV signal and multimedia signals written to orretrieved from the Blu-ray disc 212.

To process the digital TV signal 94, the system 210 includes ademodulator 96 and a transport stream demultiplexer 115 similar to thosein system 200 (FIG. 2). A TS-to-PS encoder is not required in system 210because the Blu-ray disc 212 supports direct recording of MPEG transportstreams.

To process multimedia signals retrieved from the Blu-ray disc 212, thesystem 210 includes a first signal processor 214 that demodulates anddecodes the signal 133 according to the Blu-ray Disc standard and storesthe multimedia signal in the DRAM 104. The multimedia signal output fromthe first signal processor 214 includes audio and video signals that arecompressed according to the MPEG algorithm, and can be processed by theMPEG audio and video decoder 116, the audio DAC decoder 122, the videopost-processor 126, and the TV encoder 130 for viewing and listeningsimilar to the processes described above.

To process multimedia signals that are to be recorded in the Blu-raydisc 212, the system 210 includes an audio ADC 114, a video ADC 146, anMPEG audio encoder 152, an MPEG video encoder 154, and a program streammultiplexer 160 that operate similar to those in system 200. A programstream to transport stream encoder (abbreviated as PS-to-TS encoder) 216is provided to convert the MPEG program stream generated by the programstream multiplexer 160 into an MPEG transport stream. A second signalprocessor 218 encodes and modulates the MPEG transport stream from thePS-to-TS encoder 216 according to the Blu-ray Disc standard, andgenerates an output 220 suitable for storage in the Blu-ray disc 212.

The systems 200 and 210 can be combined into one system that can recordto or read from either a DVD disc or a Blu-ray disc. When playingmultimedia content from an optical storage medium, the system controller102 detects whether the optical recording medium is a DVD disc or aBlu-ray disc, and selects the appropriate signal processing module 134or 214, respectively. When writing multimedia content to an opticalstorage medium, the system controller 102 detects whether the opticalrecording medium is a DVD disc or a Blu-ray disc, and selects theappropriate signal processor 162 or 218, respectively.

FIG. 4 shows a diagram representing the flow of signals in an example ofthe combined system when decoding audio and video signals for output tothe speaker and display. The digital TV signal 94 from the digital TVtuner 90 is processed by the demodulator 96 and the transport streamdemultiplexer 115 to generate a multimedia signal 232. A signal 132 readfrom the DVD disc 80 is processed by the first signal processor 134 togenerate a multimedia signal 234. A signal 235 read from the Blu-raydisc 212 is processed by the first signal processor 214 to generate amultimedia signal 237. The system controller 102 controls a switch 230to select the multimedia signal 232, 234, or 237, in which the selectedsignal is decoded by the MPEG A/V decoder 116 to generate a decodedvideo signal 118 and a decoded audio signal 120.

The analog audio signal 140 is converted into the digital audio signal148 by the audio ADC 144. The analog video signal 142 is converted intothe digital video signal 150 by the video ADC 146. The system controller102 controls a second switch 236 to select the decoded video 118 or thedigital video signal 150, in which the selected video signal isprocessed by the video post-processor 126 and the TV encoder 130 togenerate an output video 131. The system controller 102 controls a thirdswitch 238 to select the decoded audio signal 120 or the digital audiosignal 148, in which the selected audio signal is processed by the audioDAC 122 to generate an output audio 124.

FIG. 5 shows a signal flow diagram representing the flow of signals inthe combined system when encoding audio and video signals for storage inthe DVD disc 80 or Blu-ray disc 212. The digital TV signal 94 from thedigital TV tuner 90 is processed by the demodulator 96 and the transportstream demultiplexer 115 to generate an MPEG transport stream 232. Thetransport stream to program stream trans-encoder 166 converts the MPEGtransport stream 232 into an MPEG program stream 242.

The analog audio signal 140 is processed by the audio ADC 144 and theMPEG audio encoder 152 to generate an MPEG encoded audio signal 246. Theanalog video signal 142 is processed by the video ADC 146 and the MPEGvideo encoder 154 to generate an MPEG encoded video signal 248. Theprogram stream multiplexer 160 multiplexes the encoded audio and videosignals 246 and 248 to generate a multiplexed program stream 244. ThePS-to-TS encoder 216 converts the program stream 244 into an MPEGtransport stream 245.

The system controller 102 can detect whether the optical recordingmedium is a DVD disc or a Blu-ray disc, and select the appropriatesignal processor 162 or 218, respectively. When writing to the DVD disc80, the system controller 102 controls a switch 240 to select theprogram stream 242 or 244, in which the selected program stream isprocessed by the second signal processor 162 and recorded to the DVDdisc 80. When writing to the Blu-ray disc 212, the system controller 102controls a switch 241 to select the transport stream 232 or 245, inwhich the selected transport stream is processed by the second signalprocessor 218 and recorded to the Blu-ray disc 212.

Although some examples have been discussed above, other implementationsand applications are also within the scope of the following claims. Forexample, the DVD disc 80 can also be a CD disc, such as a CD-R(CD-Recordable) disc or CD-RW (CD-Rewritable) disc. In the aboveexamples, the DVD disc supports direct recording of MPEG programstreams, and the Blu-ray disc supports direct recording of MPEGtransport streams. The optical disc recording standards may evolve suchthat it may be possible to record MPEG transport streams in a DVD discand MPEG program streams in a Blu-ray disc. In that case, the PS-to-TSencoder 166 and the TS-to-PS encoder 216 may be omitted. Other types ofoptical recording medium may also be used, such as High-Definition DVD(HD DVD), MiniDisc, or magnetic-optical discs.

Various types of memory can be used in the systems 200 and 210. Forexample, the DRAM 104 can be synchronous DRAM, double data rate (DDR)DRAM, or reduced latency DRAM. Static random access memory (SRAM) canalso be used, including quad data rate SRAM. The memory 104 does notnecessarily have to be a single chip. The memory 104 can includemultiple banks or multiple chips. Allocation of a first portion ofmemory to store data used during the processing of the digital TV signalis partially dependent on the encoding of the video signal for opticalstorage. Similarly, allocation of a second portion of the memory tostore data used during encoding of the video signal for optical storageis partially dependent on processing of the digital TV signal.

A combined digital radio decoder and optical recording system can beimplemented using the principles described above. A common systemcontroller controls a digital radio and optical storage processingmodule, which executes a first process for processing a digital radiosignal, a second process for processing audio signals to be recorded toan optical storage medium, and a third process for processing encodedaudio signals retrieved from the optical storage medium. A common memorystores data generated by the digital radio and optical storageprocessing module while executing the first, second, and thirdprocesses. By using a common system controller and a common memory,system resources can be used more efficiently and the amount of memorycan be reduced.

For example, the user may be listening to a first digital radio programat the same time that a second digital radio program is recorded to theoptical storage medium. Or the user may be listening to a first digitalradio program at the same time that an analog audio signal is recordedto the optical storage medium. The system controller allocates a firstportion of the memory for decoding the digital radio signal, andallocates a second portion of the memory for processing the audio signalto be recorded to the optical storage medium. The system controllerdetermines the sizes of the first and second memory portions based onoperation requirements, and the sizes of the first and second memoryportions may change over time.

The system controller 102 can have many components, and does notnecessarily have to be a single chip or be embedded in a combined-systemchip. The system controller 102 controls the processing of the digitalTV signal in a way that is partially dependent on the encoding of thevideo signal for optical storage. Similarly, the system controllercontrols the encoding of the video signal for optical storage in a waythat is partially dependent on processing of the digital TV signal. Inone example, the first and second signal processors 134 and 162 are thesame signal processor executing different software code. In anotherexample, the first and second signal processors 214 and 218 are the samesignal processor executing different software code. In another example,the signal processors 134, 162, 214, and 218 are the same signalprocessor executing different software code.

1. A method, comprising: using a controller to control operations of afirst module for decoding a digital TV signal and a second module forencoding a video signal for recording to an optical recording medium;storing data used during operations of the first and second modules in ashared memory, in which allocation of a first portion of the memory tostore data used by the first module is partially dependent on anoperation condition of the second module; and adjusting speeds of thefirst and second modules so that peak requirements of the memory fromthe first and second modules occur at controlled times.